Optical codes (e.g. bar codes) store data by encoding that data using geometric patterns set by established standards (i.e. symbologies). Therefore, the stored data is retrievable by reading the geometric patterns of the optical code and decoding the geometric patterns read using the appropriate symbology. For example, bar codes may represent encoded data through a series of adjacent bars having various widths that are separated by intervening spaces with a different reflectivity than the bars they separate. Optical scanners, such as bar code readers, read the geometric pattern of bars and spaces representing encoded data by receiving a portion of an emitted optical signal that is reflected by the bar code. Based upon the received portion of the optical signal, a DBP signal is generated that represents the varying reflectivity encountered by the optical signal during the scanning operation. In doing so, the DBP signal is a representation bar code's geometric pattern of bars and spaces read during the scanning operation. The DBP signal is forwarded to a decoder that retrieves the data by decoding the bar code's geometric pattern using the appropriate symbology.
Such DBP signals exhibit a temporal resolution that is closely related to the spatial resolution of the bar code as seen by the optical scanner during the scanning operation. DBP signal characteristics like pulse duration corresponding to the widths of adjacent bars are affected by this close relation between temporal and spatial resolution. For example, as the distance between the bar code and the optical scanner increases, the DBP's pulse durations decrease. The DBP's pulse durations also decrease as the scan rate used by the optical scanner increases, such as with high performance optical scanners designed with far field reading capabilities or equipped with high scan rate modules. This is problematic for some decoders with limited processing capability, such as those equipped with CPUs having lower processing speeds to reduce the decoder's cost. If the duration of the DBP's pulse widths decreases enough, the low-cost decoders cannot adequately measure their duration of due to the CPU's limited processing capability. When the duration of the DBP's pulse widths cannot be adequately measured, the low-cost decoder cannot retrieve the encoded data being represented by the scanned optical symbol. A configurable communication interface having selectable operating modes is needed to implement communication between optical scanners and decoders with different capabilities. Such interface would enable the integration of low-cost decoders and high performance optical scanners to provide an optical symbol scanning system retaining the cost savings provided by the decoder without sacrificing the optical scanner's reading performance.